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ULS-200 Troubleshooting

How to Troubleshoot the ULS-200 Level Sensor

Considerations

Are you using the right configuration for your liquid media type?

The ULS-200 is preconfigured at the factory for either low-dielectric media like oils and hydrocarbons or high-dielectric media like water or coolant. Mid-range dielectric media like some alcohols and solvents require testing to confirm which type should be used.

Is the power supply correct?

Standard sensors require a 9 to 32 VDC input. 

Is the wiring correct?

Wiring schematics can be found in the datasheet.

Is the correct sinking or sourcing configuration being used?

Sinking and Sourcing are terms used to describe how an associated load (the device being turned on or off by the sensor) is powered in relation to the sensor. Details on sinking and sourcing can be found in the Gems website knowledge base here: Sinking or Sourcing General Overview.

Is the sensing probe clean?

Any dried-on debris that could cause a false reading? Although thin coating of the probe should not affect sensing in most cases, the sensing field around the probe can be affected if there is a large enough build-up.

Are you using an adapter? 

The sensing element face should be kept at least 0.50” (12.7mm) away from any surface on all sides. Please pay special attention when using adapters that may cause the liquid media to remain inside the cavity.

Are the application conditions within the acceptable temperature and pressure ranges?

Temperature = -40° F to +257° F (-40° C to +125° C), press = Up to 300 PSIG (20.7 bar).

Was the sensor overtightened? 

Torque specifications prevent damage to the internal components of the ULS-200. Torque specs can be found in the datasheet.

Does your circuit require protection? 

For inductive loads, you can place a diode in parallel with the inductive load to suppress fly-back voltage. The diode should be placed as close to the load as possible. The diode's breakdown voltage should be higher than the circuit's supply voltage.

Are there sources of electrical noise nearby? 

Electrical noise is the source of many problems in control circuits. Signal and sensing circuits usually operate at lower voltage levels, and the lower that voltage is, the more vulnerable it is to noise. Details on electrical noise can be found in the Gems website knowledge base here: Electrical Noise: Various Causes and How to Avoid Effects.

Best Practices for Troubleshooting

  • Completely remove the sensor from your mechanical and electrical system. This will isolate any variable in the circuitry. After removal, gently wipe the sensor to get rid of any leftover debris.
  • Bench test with room-temperature tap water or engine oil. This way, the target fluid and its properties are well-known.
  • Use a known good power supply as well as a known good voltmeter and see if the sensor 
    responds to media.
  • To check the output switching, use a 10K resistor load and connect to the output per the configuration (sinking or sourcing). Choose a resistor load that doesn't maximize the stated load current of <300mA (Load Current = Voltage / Resistor Load = < 300mA). Example: Resistor Load = 10K, Voltage = 36V DC, Load Current = (36/10,000) = 0.0036Amps = 3.6mA.
  • Substitute components: This involves replacing the suspected bad sensor with a known good one. This method can be effective in determining if the sensor itself is the root cause, but it’s inefficient and risky, as the original fault might damage the new components too. Use substitution as a last resort to avoid potentially costly damage.
  • Contact Gems’ Technical Support Team. Fill out the form here: Technical Help Request Form.